A statistical approach for polarized parton distributions

A global next-to-loading order QCD analysis of unpolarized and polarized deep-inelastic scattering data is performed with parton distributions constructed in a statistical physical picture of the nucleon. The chiral properties of QCD lead to strong relations between quarks and antiquarks distributions and the importance of the Pauli exclusion principle is also emphasized. We obtain a good description, in a broad range of x and Q(2), of all measured structure functions in terms of very few free parameters. We stress the fact that at RIIIC-BNL the ratio of the unpolarized cross sections for the production of W+ and W- in pp collisions will directly probe the behavior of the (d) over bar (x)(u) over bar (x) ratio for x greater than or equal to 0.2, a definite and important test fur the statistical model. Finally, we give specific predictions for various helicity asymmetries for the W+/-, Z production in pp collisions at high energies, which will be measured with forthcoming experiments at RIIIC-BNL and which are sensitive tests of the statistical model for Delta(u) over bar (x) and Delta(d) over bar (x).